Travel Advice - What does scale mean and how do you use it?

Map scale is the cartographer’s attempt to provide an indication of how far reality has been scaled down in order to represent geography on a piece of paper or a computer screen. Map scale is the relationship between what we can call map space (a unit of distance represented on the map) and real world space (the same distance measured in the real world).

Most often, map scale is presented as a fraction (1/2000) or a ratio (1:2000), although bar scales are, also a popular method of representing a map’s scale.

Example of a bar scale

Working with map fractions and ratios

It is important to note that the map scale, when provided as a fraction (1/2000) or a ratio (1:2000), is “measureless”. In effect, the scale represented in these forms indicates that one unit of some length on the map equals some number of the same units of length in the real world.

• For example, a scale of 1/2000 could be considered to indicate that 1inch on the map represents 2000 inches in the real world. The same scale (1/2000) could also be read as 1 centimeter of distance on the map represents 2000 centimeters of distance in the real world.
• In fact, you can use any  convenient  or familiar measure of distance to represent map scale.

Sometimes people look at map scales expressed in fractions or ratios and convert them to metrics that are more meaningful.

• For instance a map of the scale of 1/24000 can be thought of as one inch measured on the map represents a 2000 foot distance in the real world (24000/12 = 2000 feet).
• If you are comfortable thinking about distances in miles, remember that there are 63,360 inches in a mile and 5,280 feet in a mile (63360/12).
  • A map scale of 1/60000 approximates an inch on the map representing a mile in the real world (60000/63360 = .946 miles).
  • Similarly a scale of 1/500 000 approximates an inch on the map representing approximately eight miles in the real world (500 000/63 360 = 7.891).
  • A centimeter is one hundredth of a meter and there are 1000 meters in a kilometer. A map scale of 1/60 000 approximates a centimeter on the map representing 600 meters (or .6 Kilometers) in earth space.

In general, when working with scale you should consider using a unit of distance that is both convenient and common. Though you might like yards as a measure (and the British do) many maps are not a yard in extent and the measure is difficult to apply.

Working with bar scales

Most people find the use of map fractions and ratios confusing and prefer to use a bar scale, if one is provided. Bar scales make distance calculations easy, as they provide map distances in convenient, linear graphic units.

• A convenient way of using a bar scale to measure distance is to place an edge of a sheet of paper on the map and mark off the distance between two places.
  • Then, calculate the distance by comparing the length between the two marks on the paper to the length of the bar scale printed on the map.
• If your route curves, you can cut a length of string and drape it around the road curves between the locations.
  •  Pick up the endpoint of the string, straighten the string, and measure it against the bar scale to compute a more specific distance between two places.

Many people find it convenient to “eyeball “ the distance between two places by running a finger along a road, estimating each segment of road and totaling it to come up with a reasonable distance.

• If you are a real stickler for detail, you can buy an “opusometer” (a trip meter). The opusometer has an adjustable dial that can be set to the map scale and a wheel that you place on map to measure distance.
  • Simply roll the wheel along the route to the destination and the  gauge displays the measured distance converted from the map scale.
  •  Digital versions of this device (reformulated in the shape of a pen) are available at many map and travel stores.

If distance measurement sounds like too much trouble, you will be pleased to know that better quality maps often include a table showing distances between major towns shown on the map.

• Hallwag ( a map publisher located in Switzerland) provides excellent products with handy mileage tables for most European countries.
• Some maps include the distances between successive intersections and exits on major highway, printed on the map between the intersections.
  • The Rand McNally large format, Road Atlas is a good example of this useful practice.

Map scale and map detail

City street maps are considered large scale maps because they represent reality at a size that can be used to include great amounts of detail.  Country maps shown in a world atlas are small scale maps, as they are used to represent reality at a small size that allows only limited detail to be shown. 

If you will be spending your vacation in a city, you may want to purchase a large scale, highly detailed street map to help you navigate the city during your vacation.  Conversely, if you are planning a driving vacation, you will need to purchase a smaller scale road map or, perhaps a road atlas that covers a broader area in less detail than you would find on a street map.

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